It's a handling fee. I've had things take over an hour to gather everything, pack, label, etc. Mancini employees don't work for free. Now some places use the shipping dept as a profit center, although slim.
Jims auto was horrible for this type of excessive shipping charges and broomhilda answering the phones... OOOF Year one, classic are another pair that run up the charges.
Same as the part is being sold, if it isn't sold by X date - NO SHIPPING, it's going in the trash, not taking it with me. The number of I'll pay for shipping since you are tossing it away. I don't think so. :)
One of my favorites of all time was a customer that wanted something from me. Another vendor had a similar item. MY price was $20 less with about $12 shipping, they bought from the other person because they got free shipping. Paid $8 more for an inferior item. Hey, shipping was free and the swung the scales. Math is hard.